Field of Invention
The present invention relates to a semiconductor device.
Description of Related Art
In recently, the technologies of Si-based semiconductor are developed and have been mature. However, as the sizes of the semiconductor devices become smaller, it brings out some bottlenecks about the device characteristics come from the semiconductor material thereof. Many new technologies of other semiconductor device to replace Si-based semiconductor are therefore presented. The III-V group semiconductor, especially the nitride-based semiconductor material, gallium nitride for example, possesses special spontaneous polarization, high electron saturation velocity, and high breakdown electric field. Since the generation of two dimensional electron gas (2DEG) is caused by spontaneous polarization and piezoelectric polarization, the nitride-based semiconductor is received more attentions in the art.